Aiming at the problems of non-saturation attack with insufficient ammunition resources, such as being unable to ensure that important targets achieve the expected damage, or being too inefficient to be applied in engineering, a firepower allocation method considering collateral damage and damage constraints is proposed. The grouping strategy of group targets is established to consider the collateral damage of targets and improve the rationality of damage probability calculation. In order to improve the efficiency of firepower allocation, the firepower allocation problem is equivalently transformed into one-dimensional integer programming. Through two simulation examples, the results show that the method is effective, and the time consumption increases slowly with the increase of the problem scale, which can meet the requirements of engineering application.